Advanced oxidation of photographic processing effluents on novel heterogeneous fibrous catalyst

Abstract

A novel heterogeneous catalyst, based on Fenton’s chemistry, was evaluated for the treatment of KODAK Silver Bearing (SB) photographic processing effluents with high Chemical Oxygen Demand (COD) value. The effect of temperature, the nature and concentration of the oxidant (air and/or hydrogen peroxide), the duration of catalytic treatment and the dilution factor of the effluent on the reduction in COD were investigated. The catalyst and bubbled air (with no hydrogen peroxide present) resulted in a significant COD reduction of the effluent of 56 % after 18 hours of treatment at room temperature. It was found that most of the COD reduction occurred within the first four hours of treatment. Using air on its own, as oxidant was found to be sufficient, with only a slight improvement on the addition of hydrogen peroxide. Ambient temperature was preferred for the catalytic treatment of the effluent, as an increase in temperature up to 60C led to less COD reduction which may arise from a change in the redox potential of the active transition metal (Fe) complex or to the formation of recalcitrant products.